<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<link href="1.css" rel="stylesheet" type="text/css"/>
	</head>
	<body>
		<div class="a">
		<div id="father">
			<div id="first">第一个盒子</div>
			<div id="second">第二个盒子</div>
			<div id="third">第三个盒子</div>
		</div>
		</div>
	</body>
</html>
